Various means have been utilized in the past in the attempt to prevent the flow of fluid between the head and case. These attempts have not been entirely satisfactory.
One apparatus which has been used is the use of O-rings in a male gland type joint, but they are extruded through gaps between the pump case and head during case pressurization.
N. H. Sachink illustrated an annular responsive lip as part of the seat of a ball check valve in his pump described in U.S. Pat. No. 3,327,635 issued June 29, 1967.
A similar pressure-responsive lip arrangement was utilizd in a packing ring presented by R. E. Henry in U.S. Pat. No. 3,685,840 issued Aug. 22, 1972.
However, the pressure-responsive lip alone is unsatisfactory in providing a fluid tight seal in a large cylindrical pump.
Macks in U.S. Pat. No. 3,093,382 described a self-balancing seal as a combination thrust bearing and seal which provides a fluid seal which is movable along the path of fluid escape. However, it is unsuitable for use in a pressurized pump case because no leak can be tolerated.
It is an object of this invention to provide an improved sealing means for cylindrical pump cases or the like that effectively prevents leakage between the head and case.